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Biomedical subjects

E Volger

Publications and source records attributed to E Volger.

At least 37 records · Page 2Linked to original sources
PubMed1976

[Treatment of bradycardiac arrhythmias with depot-orciprenaline (author's transl)].

24 patients with bradycardiac arrhythmias of various origin were treated with a new depot preparation of orciprenaline. The special galenical preparation guarantees effectiveness ofr 8-10 hours. In 21 patients (87%), therefore, one dragee morning and evening was sufficient to obtain a mean rise in frequency of 57%. The preparation had to be discontinued in 3 cases because of side effects such as increase in ventricular extrasystoles, anginal complaints and critical rise of blood pressure in hypertension. Because of its trouble-free administration in a depot form the preparation not only offers a practical advantage over the short-acting commercial preparations, but also shows a reliable efficacy. It can therefore be given under regular supervision in all forms of bradycardiac arrhythmias with stable ventricular frequency and satisfactory cardiac output.

Aged↗
PubMed1976

Red cell aggregation in blood flow. I. New methods of quantification.

The rheological behavior of normal and pathological red cell aggregates in viscometric flow (artificial flow in cone plate chamber) is studied by direct microscopy, (rheoscopy) viscometry and photometry. Marked differences between normal and pathological blood are measured in the microrheological properties of red cell aggregates; only discreet differences are measured by blood viscometry (macrorheology). Both in normal and abnormal blood, red cell aggregation is a reversible process in the presence of adequate shear forces; their respective influences on apparent blood viscosity at low rates of shear are complex functions of shear rate, shear time, hematocrit and plasma viscosities. Pathological red cell aggregation (RCA) forms more rapidly and extensively than normal RCA. The pathological aggregates frequently have a tendency to grow at low rates of shear and they are highly shear resistant.

Adolescent↗
PubMed1976

Red cell aggregation in blood flow. II. Effect on apparent viscosity of blood.

The apparent viscosity of blood strongly increases at low shear in rotational viscometers, this phenomenon is based on the reversible formation of red cell aggregates. The magnitude of this increase strongly depends on the hematocrit value, on plasma viscosity and lastly on the microrheological properties of the aggregates. The independent measurement of the microrheological behavior and the effects on viscosity allows a detailed analysis of the hemodynamic effects of red cell aggregates under defined flow conditions in vivo. The comparative analysis shows that the conventional viscometry strongly underestimates the rheological differences between normal and pathologically intensified aggregation. Based on detailed analysis under defined flow conditions in vitro, the biological significance of viscometric results and the hemodynamic relevance of red cell aggregates are discussed.

Adolescent↗
PubMed1976

Red-cell aggregation and red-cell deformability in diabetes.

The anomaly of the viscosity of human blood is more pronounced in diabetics. This is caused by an increase in plasma viscosity, a more pronounced red-cell aggregation, and a reduction of individual cell deformability. The changes in viscosity and in red-cell aggregation both are the consequence of abnormal plasma proteins, the incidence of which is largely independent of the onset and duration of disease, and actual metabolic state. The presence of complicating infectious diseases further aggravates the pathologic red-cell aggregation. The decreased red-cell deformability is largely independent on onset, duration, and complications but depends critically in the incident metabolic control of the diabetics. The possible role of hemorrheologic factors in the development of microangiopathy is discussed.

Blood Proteins↗
PubMed1975

[Electrocardiographic changes in electrolyte inbalance. Part 2: Alterations in serum calcium (author's transl)].

74 patients (hypocalcemia: 41 patients, hypercalcemia 13 patients, 20 patients as control) without heart disease were examined. A prolongation of the relative QT-interval was found in 90% and a flat or inverted T-wave in 25% of the patients with hypocalcemia. In 77% of the patients with hypercalcemia the QT-interval was shortened. A good, clinically useful correlation between the QT-interval and the serumcalcium-concentration could be established in patients with hypo- and hyper-calcemia.

Action Potentials↗
PubMed1975

[Electrocardiographic changes in electrolyte imbalance. Part 1: Alterations in serum potassium (author's transl)].

163 patients (95 hypokalemic, 48 hyperkalemic, 20 healthy) were examined. Electrocardiographic patterns of hypokalemia were evident in 46 p.c. of all patients with serum potassium less than 3,5 mval/l. Patients without cardiac disease showed signs of hypokalemia in the ECG in 68 p.c., those cases with extremly low serum potassium (less than 2,5 mval/l) in 81 p.c. In patients without cardiac disease a good correlation could be observed between ST depression and T wave inversion on one side and serum potassium level below 3,5 mval/l on the other side. The T/U ratio was found to be below unity in only 9 p.c. in mild hypokalemia, but in 82 p.c. in severe hypokalemia. ECG pattern of hyperkalemia could be found in 29 p.c. of all patients with serum potassium levels greater than 5,1 mval/l. These signs were evident in patients without cardiac disease in 29 p.c. in mild hyperkalemia, but in 75 p.c. in severe hyperkalemia. Patients suffering from cardiac disease, however showed the correspondive ECG changes of hyperkalemia only in 5 p.c. There is a good correlation between the P, and T-wave-amplitude and the serum potassium level greater than 5,1 mval/l. According to our findings it can be stated, that the ECG changes in patients with cardiac disease tend to hide the correspondive changes of potassium disorder.

Action Potentials↗
PubMed1975

Microrheology and light transmission of blood. III. The velocity of red cell aggregate formation.

The formation of primary (rouleaux) and secondary (rouleaux networks) RCA was studied by microcinematography (12 frames/sec) and photometry in a counterrotating "rheoscope" chamber. The blood was first subjected to rapid viscometric flow (460 sec-1, all RBC dispersed and aligned in flow) and then brought abruptly to full stop. In normal human blood, primary and secondary RCA occurred simultaneously, and were completed within 8 to 10 sec after stop. Blood from pregnant women at term, known for its pronounced red cell aggregation, shows a dissociation between the formation of short primary rouleaux (initiated even before full stop and completed 1-2 see thereafter) and secondary RCA completed 3-5 see after stop. RCA increases the light transmission of blood (measured by an increase in photovoltage V), the process and its first derivative (dV/dt equals I) can be recorded. After flow stop, there is an exponential decay of I(I equals t-I-o with e-lambda-t). The half time of this decay is recorded and correlated to the kinetics of red cell aggregate formation In human blood the half time of this process varies between 1.0 and 6.0 sec. In suspensions of human RBC in artificial plasmas, t-1/2 decreases with increasing concentration of fibrinogen and/or Dextran 250000, the second component appearing at concentrations above 500 mg-%. The method lend sitself for the quantification of RCA in small blood samples (20 mul).

Blood Viscosity↗
PubMed1975

Microrheology and light transmission of blood. IV. The kinetics of artificial red cell aggregation induced by Dextran.

Employing both microscopic and photometric methods the rheology of pathological red cell aggregation was studied in model experiments. Suspensions of washed human red blood cells in dextran solutions containing rising concentrations of dextrans (M.W. 40000, 70000, 110000, 250000, 500000) were used. At low concentrations (less than 500 mg-%) of high molecular weight dextrans (greater than 70000) red cell suspensions formed aggregates similar to the ones found in normal human blood. At higher concentrations, the aggregates were similar to those observed in pathological human blood. The aggregates were studied under the condition of stasis, slow flow and at shear rate of their hydrodynamic dispersion. Besides, the flow behavior of the dispersed cells at high shear rates was studied. We found: 1. In all samples the rate of spontaneous aggregate re-formation in stasis (following hydrodynamic desaggregation) rose with rising dextran concentration up to 5.0 g-%. 2. The shear resistance of the aggregates, as measured by the shear stress necessary to keep them dispersed, rose up to concentrations of 2.5g-%, but fell at higher concentrations. 3. Only with dextran of a molecular weight above 110000 coarse agglomerates could be produced at high concentrations. Loose elastic meshes were rapidly produced at high concentrations of Dx 70. 4. When subjected to steady state low shear (m sec-1) only the agglomerates, but not the meshes rapidly grew in size. Most of the aggregation kinetics recorded by photometry and microscopy evaded detection by viscometry.

Blood Viscosity↗